This invention relates to mine brattice installations and more particularly, it concerns an improved system and method for mounting a malleable sheet metal barrier on a jack post supported peripheral framework in an underground mine tunnel.
In commonly assigned U.S. Pat. No. 3,972,272, issued Aug. 3, 1967 to James Allen Bagby, there is disclosed a mine brattice structure in which a gas impervious barrier of malleable sheet metal, such as aluminum, is affixed to a yieldable peripheral framework in turn supported by shear pin retained, telescopic jack posts spaced from each other in the general plane of the brattice. An essentially air-tight seal between the sheet metal barrier and the wall surfaces defining the interior tunnel periphery in which the brattice is placed is achieved by bending, hammering or otherwise deforming the edges of the malleable sheet metal into engagement with the interior tunnel surfaces.
In the installation of such brattices, the jack posts are first placed between the mine tunnel floor and roof to be appropriately spaced across the width of the tunnel. Once the jack posts are installed, a framework of slotted beams are bolted to each other and to the jack posts so as to conform roughly with the inner periphery of the tunnel. The air impervious sheet metal barrier is then mounted to the framework and deformed into sealing engagement with the tunnel surfaces to complete the brattice installation.
Because the intended function of the brattice is to provide a barrier against air or gas flow in mine ventilating systems, the pressures to which the brattice is subjected can be substantial and require that the sheet metal be attached to the jack post supported framework securely. In light of this, threaded bolts and nuts have been preferred to achieve the needed mounting strength for the sheet metal barrier and also to minimize leakage of air or gas.
While both sides of the brattice are most generally accessible, considerable time has been required for the installation of such brattices particularly in the bolting attachment of the sheet metal barrier to the framework. Not only has this operation required two people, one on each side of the brattice being installed, but the difficulty of coordination between the two people particularly during the final stages of installation has been found tedious and time consuming.